Material presentation device

ABSTRACT

A material presentation device connecting at least two material presentation devices to each other, comprises a first selecting device for selecting one image as a main image from plural images composed of an image output by another material presentation device, a camera image of a material on a material mounting pedestal, which is photographed by a photographing section, an image stored in a memory device, and an external image output by an external device connected thereto, a second selecting device capable of selecting no image or one image as an additional image from plural images composed of a camera image of a material on the material mounting pedestal, which is photographed by the photographing section, an image stored in the memory device and an external image output by the external device, a point image generating device for generating a point image from point information which is subtracted from an image photographed by the photographing section, an image synthesizing section for synthesizing the additional image selected by the second selecting device and the point image with the main image selected by the first selecting device, a display image selecting device for selecting one image from an image output by another material presentation device and the image synthesized by the image synthesizing section, an image displaying section for displaying the image selected by the display image selecting device, and an image outputting section for outputting the image synthesized by the image synthesizing section.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a material presentation device which isequipped with a photographing section and an image displaying section,wherein at least two material presentation devices performcommunications of images with each other and share images which aredisplayed on the image displaying sections.

2. Description of the Related Art

In recent years, material presentation devices have been widely used asimage displaying devices for presentations instead of OHPs (overheadprojectors). These material presentation devices are used so that aphotographing section, which is equipped with a camera, photographs amaterial, and the image photographed by the photographing section isprojected onto a monitor and a screen as a reference image. In thiscase, documents and pictures can be used as materials as they are, andthree-dimensional objects, for example, models, can be used as objects.The material presentation devices are thereby much more useful thanOHPs. Some of material presentation devices can receive images fromexternal devices, for example, personal computers, and can output theimages.

In a presentation, generally, a presenter often gives an explanation byindicating a specific part of a reference image with a pointer. In thiscase, the presenter performs a pointing operation on an image, which isoutput by an external device, either by using the external device on theside thereof (for example, operating a pointer with a mouse when using apersonal computer) or by directly indicating a part of a display imageon a monitor or a screen. In the former case, however, the operation isperformed away from a material presentation device, thereby beingtroublesome. The latter case is not preferable since the view of thedisplay image is blocked. To overcome the above problems, a method, inwhich a photographing section photographs the state in which a pointingoperation is performed and a point image is synthesized with an externalimage which is output by an external device, is disclosed in JapanesePatent Unexamined Application Publication No. 2000-341588. A materialpresentation device, which is of increased value by the above method, isdisclosed in Japanese Patent No. 3201707.

In meetings or in educational presentations, for example, communicationsand discussions are given with reference to common images between twopersons who are far away from each other. Material presentation devicesare under consideration as tools, which are used in the above cases, formutual communications of images. In this case, if indicating marks orunderlines were added to the images, it may be easy to understand thecommunications and may be flexible to have communications. It may bepossible to add another image to the images by an image synthesizingfunction such as of the material presentation devices which aredisclosed in the above publications. These material presentationdevices, however, simply output and display a synthesized image, wherebyit is not possible for two or more material presentation devices to beused so that these devices repeatedly synthesize additional images witheach other and share synthesized images each time. The above functionmay be executed by adding exclusive image processing devices thereto,whereby, however, the system in which these devices are used iscomplicated, and the operations thereof are troublesome. In addition,the system incurs high cost due to the exclusive image processingdevices.

Thus, it was supposed that the material presentation devices may beequipped with an image synthesizing section, and communicate and share asynthesized image among each other. In this system, however, capacitiesfor image data which is communicated with each other are large, wherebycommunications and displaying images are time consuming, and theseactions may not be executed smoothly.

SUMMARY OF THE INVENTION

An object of the present invention according to an aspect of theinvention is to provide a material presentation device which enablessynthesizing an additional image or a point image with a main image andcommunicating among each other using two or more material presentationdevices, and can realize these functions with a simple structure.

An object of the present invention according to another aspect of theinvention is to provide a material presentation device which enablessynthesizing an additional image with a main image and sharing asynthesized image each time, can realize these functions by easyoperations with a simple structure, and can execute these actionssmoothly.

The present invention provides a material presentation device connectingat least two material presentation devices to each other, comprising: afirst selecting device for selecting one image as a main image fromplural images composed of an image output by another materialpresentation device, a camera image of a material on a material mountingpedestal, which is photographed by a photographing section, an imagestored in a memory device, and an external image output by an externaldevice connected thereto; a second selecting device capable of selectingno image or one image as an additional image from plural images composedof a camera image of a material on the material mounting pedestal, whichis photographed by the photographing section, an image stored in thememory device and an external image output by the external device; apoint image generating device for generating a point image from pointinformation which is subtracted from an image photographed by thephotographing section; an image synthesizing section for synthesizingthe additional image selected by the second selecting device and thepoint image with the main image selected by the first selecting device;a display image selecting device for selecting one image from an imageoutput by another material presentation device and the image synthesizedby the image synthesizing section; an image displaying section fordisplaying the image selected by the display image selecting device; andan image outputting section for outputting the image synthesized by theimage synthesizing section.

According to the present invention, for example, the materialpresentation devices are placed at two positions which are far away fromeach other, and forms of information exchanges such as in meetings or ineducational presentations can be executed while an image, which isdisplayed on both image displaying sections, is shared. The “sharing animage” of the present invention is a state in which the respectivematerial presentation devices can maintain the same image, and the sameimage can be seen simultaneously. In the present invention, asynthesized image, which is made by synthesizing the additional imageand the point image with the main image, can be shared. The main imageis an original image to which the additional image or the point image isadded. An image is selected as the main image from the above images ofone material presentation device by the first selecting device thereof,and the image displaying devices are selected appropriately, whereby theselected main image is displayed on the image displaying sections ofboth material presentation devices. The additional image or the pointimage can be added to the main image by using both material presentationdevices. The additional image is one which is selected from the aboveimages by the second selecting device. The point image is generated fromthe point information which is subtracted from the image photographed bythe photographing section.

According to the present invention, in the above manner, plural userscan add additional images or point images to the main image, canexchange and share the synthesized image with each other, andsimultaneously communicate with each other based on the shared image.The material presentation device itself has the above synthesized imagedisplaying function, whereby conventional image processing devices arenot necessary, a structure of a material presentation device for sharingan image is designed simply, and operation thereof can be easy.

The present invention further provides a material presentation deviceconnecting at least two material presentation devices to each other,comprising: a selecting device for selecting one image as a main imagefrom plural images composed of an image output by another materialpresentation device, a camera image of a material on a material mountingpedestal, which is photographed by a photographing section, an imagestored in a memory device, and an external image output by an externaldevice connected thereto; a point image generating device for generatinga point image as an additional image from point information output byanother material presentation device and point information which issubtracted from an image photographed by the photographing section; animage synthesizing section for synthesizing the main image selected bythe selecting device with the additional image generated by the pointimage generating device; an image displaying section for displaying theimage synthesized by the image synthesizing section; a first outputtingsection for outputting the main image which is selected from pluralimages composed of the camera image of a material on the materialmounting pedestal, which is photographed by the photographing section,the image stored in the memory device, and the external image output bythe external device connected thereto; a second outputting section foroutputting point information which is subtracted from the imagephotographed by the photographing section; a first inputting section forinputting the main image which is output by the first outputting sectionof another material presentation device; and a second inputting sectionfor inputting point information which is output by the second outputtingsection of another material presentation device.

According to the present invention, for example, the materialpresentation devices are placed at two positions which are far away fromeach other, and forms of information exchange such as in meetings oreducational presentations can be executed while an image, which isdisplayed on both image displaying sections, is shared. The “sharing animage” of the present invention is a method in which the respectivematerial presentation devices can maintain the same image and the sameimage can be seen simultaneously. In the present invention, asynthesized image, which is made by synthesizing the point image withthe main image, can be shared. The main image is an original image towhich the point image is added. The point image is one image based onthe point information photographed by the photographing section.

According to the present invention, an image is selected as the mainimage from the above images of one material presentation device by theselecting device thereof. On the part of one material presentationdevice, the main image is input into the image synthesizing section, andis displayed on the image displaying section. Also, the main image isinput from the first outputting section into the first inputting sectionof another material presentation device, and is displayed on the imagedisplaying section thereof, whereby the main image is shared with bothmaterial presentation devices. Next, a pointing operation is performedon the main image using one material presentation device, and thepointing action is photographed by the photographing section thereof. Onthe part of one material presentation device, a point image is therebygenerated based on the point information by the point image generatingdevice, and the point image is synthesized with the main image by theimage synthesizing device thereof. The point information is output fromthe second outputting section of one material presentation device intothe second inputting section of another material presentation device. Onthe part of another material presentation device, a point image isgenerated based on the point information by the point image generatingdevice, and the point image is synthesized with the main image by theimage synthesizing device, whereby the synthesized image which is madeby synthesizing the point image with the main image is displayed on theimage displaying sections of both material presentation devices. In thepresent invention, these operations are repeatedly performed among eachother by the material presentation devices. The point information of thepresent invention is information which is needed to generate the pointimage, which is, for example, related to the shape, position, size, andcolor of the point image, and only the point information is exchangedwith each other by the material presentation devices.

According to the present invention, in the above manner, plural userscan add additional images or point images to the main image, exchangeand share the synthesized image with each other, and simultaneouslycommunicate with each other based on the shared image. The materialpresentation device itself has the above synthesized image displayingfunction, whereby conventional image processing devices are notnecessary, a structure of the material presentation device for sharingan image is designed simply, and operation thereof can be easy. Inaddition, instead of outputting the synthesized image, which is made bysynthesizing the point image with the main image, to another materialpresentation device, only the point information which is needed togenerate the point image is output, another material presentation devicewhich accepts the point information generates a point image by the pointimage generating device, and synthesizes the point image with the mainimage by the image synthesizing section. Thus, the output pointinformation is much smaller than images (image data) in informationcontent and in the capacity therefor, whereby communication traffic isgreatly reduced. As a result, it is possible to reduce the time forcommunicating and displaying images, and to make image displayingactions smoother.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a state in which image data andvoice data are communicated using two material presentation devices inthe first embodiment according to the present invention;

FIG. 2 is an image selecting panel which is provided on the materialpresentation device in the first embodiment according to the presentinvention;

FIG. 3A is a functional block diagram of one material presentationdevice, and FIG. 3B is a flow chart showing an image synthesizingoperation thereof in the first embodiment according to the presentinvention;

FIG. 4A is a functional block diagram of the other material presentationdevice, and FIG. 4B is a flow chart showing an image synthesizingoperation thereof in the first embodiment according to the presentinvention;

FIG. 5 is a flow chart of an image, showing an image synthesizingprocess in the first embodiment according to the present invention;

FIG. 6 is a diagram of one example of a synthesized image in a case ofusing the material presentation device in an educational presentation inthe first embodiment according to the present invention;

FIG. 7 is a diagram showing a state in which three material presentationdevices are connected to each other in the first embodiment according tothe present invention;

FIG. 8 is a schematic diagram showing a state in which image data andvoice data are communicated using two material presentation devices inthe second embodiment according to the present invention;

FIG. 9 is an image selecting panel which is provided on the materialpresentation device in the second embodiment according to the presentinvention;

FIG. 10A is a functional block diagram of one material presentationdevice, and FIG. 10B is a flow chart showing an image synthesizingoperation thereof in the second embodiment according to the presentinvention;

FIG. 11A is a functional block diagram of the other materialpresentation device, and FIG. 11B is a flow chart showing an imagesynthesizing operation thereof in the second embodiment according to thepresent invention;

FIG. 12 is a flow chart of an image, showing an image synthesizingprocess in the second embodiment according to the present invention;

FIG. 13 is a diagram showing a state in which three materialpresentation devices are connected to each other in the secondembodiment according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described hereinafter withreference to the drawings.

(1) First Embodiment

(A) Constitution of Material Presentation Device

FIG. 1 systematically shows a state in which image data and voice dataare communicated by material presentation devices 101 and 102(hereinafter these material presentation devices are called devices 101and 102 for short) in a first embodiment according to the presentinvention. The devices 101 and 102 have the substantially samestructure, and reference numerals of the components in the device 102are attached with an affix“′” to the reference numerals of thecomponents in the device 101. Since the components in the device 102 areidentical to those of the device 101, detailed explanations for thecomponents in the device 102 will be omitted. The device 101 is equippedwith a material mounting pedestal 111, a photographing section 113,provided on the material mounting pedestal 111 via an arm 112, whichphotographs a material S1, for example, a document, on the materialmounting pedestal 111, a display (image displaying section) 114, and aspeaker-microphone 115 which inputs and outputs voice. The display 114is provided at the back side of the set position of the material on thematerial mounting pedestal 111, and is set at a backward inclinedattitude toward a user (not shown) who is in front of the materialmounting pedestal 111.

The photographing section 113 is equipped with a camera 113 a and anoptical filter 113 b which enables the camera 113 a to photograph onlyinfrared light. The optical filter 113 b is removably placed in thephotographing optical path of the camera 113 a. The optical filter 113 bis switched between a state of being placed in the photographing opticalpath and a state of being removed therefrom by hand or by automaticcontrol. In the state of being removed therefrom, the camera 113 aphotographs the material S1, and a photographed image by the camera 113a is displayed on the display 114.

In FIG. 1, reference numeral 120 denotes a pen which is used toindicate, for example, a specific part of the material S1 by the user. Apointing mark 121 is provided at the leading tip portion of the pen 120which emits infrared light. The pointing mark 121 is composed of a lightemitting diode (LED) which emits light by changing a switch to ON. Theuser performs a pointing operation on a required part with the pointingmark 121 of the pen 120.

An image which is displayed on the displays 114 and 114′ of the devices101 and 102 is input into and output to each other, and the same imageis displayed on the displays 114 and 114′. That is, the same image isshared with the devices 101 and 102. The voice data which are input intothe speaker-microphones 115 and 115′ are input into and output to eachother, and the voice data which are input into the speaker-microphone115 of the device 101 are output from the speaker-microphone 115′ of thedevice 102. A mutual communicating device for images and voice data areselected appropriately according to the set positions of the devices 101and 102 or interfaces. The mutual communicating device is composed of acable 130 for communication in FIG. 1.

The above devices 101 and 102 enable communicating usingspeaker-microphones 115 and 115′ while sharing an image displayed on thedisplays 114 and 114′, enable synthesizing of an additional image with amain image displayed on the displays 114 and 114′ among each other, andenable sharing of the synthesized image each time.

The main image is shared by the devices 101 and 102. On the part of thedevice 101, a camera image (an object of the camera image is thematerial S1, etc.) which is photographed by the camera 113 a is selectedas the main image. A memory image is stored in an internal memory devicewhich is provided in the device 101 or in an external memory devicewhich is removably placed in the device 101. An external image which isgenerated from an external device, for example, a personal computer,connected to device 101, is selected as the main image. An image by thedevice 102, which is input from the device 102 into the device 101, isselected as the main image. The camera image, the memory image or theexternal image by the device 101 is selected as an additional imagewhich is synthesized with the main image. The image displayed on thedisplay 114 is set to be an image either by the device 101 itself or bythe device 102.

As shown in FIG. 2, an image selecting panels 116 is provided on thedevices 101. The image selecting panel 116 has buttons which decidewhich of the above images is respectively selected as the main image,which of the above images is selected as the additional image, and whichof images by the device 101 itself and by the device 102 is displayed onthe display 114.

Buttons for selecting the main image are provided on a main imageselecting section (first selecting device) 170, and are composed of aninput 11A button 171 for selecting the output image from the device 102,a camera button 172 for selecting the camera image by the device 101, amemory button 173 for selecting the memory image of the device 101, apersonal computer button 174 for selecting the external image which isinput from the external device (in this case, a personal computer), anda reserve button 175 for selecting one image other than these images.

Buttons for selecting additional images are provided on an additionalimage selecting section (second selecting device) 180, and are composedof a camera button 181 for selecting camera images, a memory button 182for selecting memory images, a personal computer button 183 forselecting external images, and a reserve button 184 for selecting imagesother than these images. In the case of selecting the additional image,the above images are of the device 101 itself. Buttons for selecting theimage displayed on the display 114 are provided on a display imageselecting section (display image selecting device) 190, and are composedof an input 11A button 191 for selecting the output image from thedevice 102 and a synthesizing image button 192 for selecting thesynthesized image.

FIG. 3A is a functional block diagram showing the execution of an imagesynthesizing function using the device 101, and FIG. 4A is the samefunctional block diagram in the case of using the device 102. Thefigures facilitate understanding the processes for images which areinput into and output from these devices, in “operation of materialpresentation device” as described below, although these devices have thesame structure. Explanations for the execution of an image synthesizingfunction using the device 102 will be omitted.

The device 101 has an image synthesizing circuit (image synthesizingsections) 140 which synthesizes plural input images by an ordinary imagesynthesizing method. The image by the device 101 or the image outputfrom the device 102 is input as the main image into the imagesynthesizing circuit 140. One image is selected as the main image of thedevice 101 from the camera image, the memory image and the externalimage, by a third selector 163. The main image is input into a firstframe memory 151 via an input line 141, and is temporary stored therein.The image output from the device 102 is input from an input 11A into asecond frame memory 152 via an input line 142, and is temporary storedtherein. The image by the device 101 or the image output from the device102 is selected by a first selector 161, and is input as the main imageinto the image synthesizing circuit 140. In this case, changingoperations of setting the third selector 163 and of setting the firstselector 161 are respectively performed by pressing one of the buttons171 to 174 of the main image selecting section 170 on the above imageselecting panel 116.

The additional image which is added to the main image is directly inputfrom an input line 143 into the image synthesizing circuit 140, and apoint image is directly input from a point image generating section(point image generating device) 145 thereinto. No image or one image isselected as the additional image, which is input from the input line 143into the image synthesizing circuit 140, by a fourth selector 164. Inthis case, a changing operation of setting the fourth selector 164 isperformed by pressing no button or one of the buttons 181 to 183 of theadditional image selecting section 180 on the above image selectingpanel 116. The point image is generated from point information, which issubtracted from the image photographed by the photographing section 113,by the point image generating, and the point image is directly inputinto the image synthesizing circuit 140. Generating a point image isdescribed in “pointing function with a pen” hereinafter.

The additional image selected by the fourth selector 164 is synthesizedwith the main image, which is selected by the first selector 161, by theimage synthesizing circuit 140. The point image is synthesized with themain image when the point image is generated by the point imagegenerating section 145. The synthesized image is output from an output11B to the device 102. Also, the synthesized image is input into asecond selector 162. An image output from the device 102 is input fromthe second frame memory 152 into the second selector 162. The imageoutput from the device 102 or the synthesized image is selected by thesecond selector 162, and is output to the display 114. In this case, achanging operation of setting the second selector 162 is performed bypressing one of the buttons 191 and 192 of the display image selectingsection 190 on the above image selecting panel 116.

(B) Pointing Function with a Pen

In the case of the device 101, a pointing operation can be performed ona specific part of the material SI on the material mounting pedestal 111using the photographing section 113 and the pointing mark 121 of the pen120 without the shadow of the pen 120 and the user's hand falling on adisplaying screen. The action of the pointing function of the device 101is described below. Explanations for the action of the pointing functionof the device 102 will be omitted since the action thereof is the sameas that of the device 101.

XY coordinates of a virtual screen are set within a photographing viewangle of the camera 113 a on the upper surface of the material mountingpedestal 111, that is, the material mounting surface, by an ordinaryimage analysis. A method of setting the virtual screen is describedbelow. The pointing mark 121 of the pen 120 emits light in turn at twodiagonal corner points at least within the photographing view angle ofthe camera 113 a while the optical filter 113 b is placed in thephotographing optical path. The above state in which the pointing mark121 of the pen 120 emits light is photographed by the camera 113 a, andthe positions of the pointing mark 121 which are light emitting pointsare recognized based on the image data by the camera 113 a. The XYcoordinates of the virtual screen are generated by an image processingtechnique. As a result, the invisible virtual screen is set on thematerial mounting pedestal 111, and is fixed as long as the intervalbetween the camera 113 a and the material mounting pedestal 111 is notchanged. That is, the operation of setting the virtual screen may beperformed once as an initial setting. When the material S1 is placed onthe material mounting pedestal 111 and a pointing operation is performedthereon, the virtual screen is set within the overall photographing viewangle, whereby it is possible to perform a pointing operation directlyon the position of the material S1.

When the material S1 is placed on the material mounting pedestal 111,the virtual screen is set on the material S1. When a pointing operationis performed, the pointing mark 121 of the pen 120 emits light on thematerial S1 while the optical filter 113 b is placed in thephotographing optical path. As a result, the pointing mark 121 isphotographed by the camera 113 a, and the position coordinates of thepointing mark 121 on the coordinates of the virtual screen aresequentially calculated based on the image data. The point image whichis in a shape of, for example, an arrow, is generated on the positioncoordinates of the pointing mark 121 which are calculated by the pointimage generating section 145. The point image is directly input into theimage synthesizing circuit 140, and is synthesized with the main imagewhich is input thereinto.

(C) Operation of Material Presentation Device

An example of operations of the above material presentation devices 101and 102 is described hereinafter.

[Device 101]

FIG. 3B is a flow chart showing the operation of the device 101. Asshown in the figure, the image either by the device 101 or by the device102 is selected as the main image by the device 101, and one image isselected as the main image from the above images when the image by thedevice 101 is selected as the main image (in step S111). In this case,an image A1 by the device 101 is selected as the main image, and one ofthe buttons 172 to 174 of the main image selecting section 170 on theabove image selecting panel 116 is pressed. As a result, the image A1which is set to be the main image on the part of the device 101 is inputinto the image synthesizing circuit 140.

Next, the input 11A button 191 of the display image selecting section190 is pressed, the image output from the device 102 is selected as theimage displayed on the display 114 (in step S 112). A pointing operationis performed on the material S1 of the device 101 using the pointingmark 121 of the pen 120 as described above (in step S113), whereby apoint image a1 is input from the point image generating section 145 intothe image synthesizing circuit 140. In this case, the additional imageis not selected at all.

[Device 102]

As shown in a flow chart in FIG. 4B, in the case of the device 102, theimage either by the device 101 or by the device 102 is selected as themain image which is shared with the devices 101 and 102 (in step S 121).In this case, since the image A1 by the device 101 is selected as themain image as described above, the input 11A′ button 171′ of the mainimage selecting section 170′ on the image selecting panel 116′ ispressed, whereby the image output from the device 101 is input as themain image of the device 102 into the image synthesizing circuit 140′.

Next, the synthesized image button 192′ of the display image selectingsection 190′ is pressed, the synthesized image output from the imagesynthesizing circuit 140′ is selected as the image displayed on thedisplay 114′. In the case of the device 102, the additional image by thedevice 102 is not selected at all in the same manner as the device 101,and a pointing operation is performed using the pointing mark 121′ ofthe pen 120′ on the material S1′ (in step S123), whereby a point imageb1 is input from the point image generating section 145′ into the imagesynthesizing circuit 140′.

By the above settings of the devices 101 and 102, the point image a1 issynthesized with the main image A1 by the image synthesizing circuit 140of the device 101, the synthesized image A1+a1 is input from the output11B into the input 11A′ of the device 102 via the cable 130, and thesynthesized image A1+a1 is displayed on the display 114′ of the device102 (in step S122 in FIG. 4B). While seeing the synthesized image A1+a1on the display 114′, the user of the device 102 performs a pointingoperation on a desired part of the synthesized image A1+a1 using thepointing mark 121′ (in step S123 in FIG. 4B). The synthesized imageA1+a1 output from the device 101 is input from the input line 142′ intothe image synthesizing circuit 140′ of the device 102, and the pointimage b1 is synthesized with the synthesized image A1+a1 by the imagesynthesizing circuit 140′ thereof. The synthesized image A1+a1+b1 isdisplayed on the display 114′ of the device 102, is input from theoutput 11B′ into the input 11A of the device 101 via the cable 130, andis also displayed on the display 114 of the device 101 (in step S114 inFIG. 3B and in step S124 in FIG. 4B). The synthesized image A1+a1+b1which is displayed on the displays 114 and 114′ is shared with the usersof device 101 and 102.

Next, when an image B1 by the device 102 is selected as the main image,image synthesizing operations proceed in the above manner as shown insteps S115 to S 117 in FIG. 3B and in steps S125 to S127 in FIG. 4B.

FIG. 5 shows the above operations of image synthesizing in time sequencein turn, which are divided between parts of the devices 101 and 102. Amain image A11, a point image all (arrow), and a point image b11(underline) respectively correspond to the main image A1, the pointimage a1, and the point image b1. FIG. 5 shows operations in which apointing operation is performed on a part of the main image A12 againusing the device 101, the point image a12 is thereby synthesized withthe main image A12, and the synthesized image A12+a12 is output to thedevice 102. A pointing operation is performed on a part of thesynthesized image A12+a12 again using the device 102, the point imageb12 is thereby synthesized with the synthesized image A12+a12, and thesynthesized image A12+a12+b12 is displayed on the displays 114 and 114′of the devices 101 and 102. As a result, it is possible to add the pointimage to the synthesized image which is output to the displays 114 and114′ of the devices 101 and 102 and is shared with the devices 101 and102. In this case, it is possible to communicate usingspeaker-microphones 115 and 115′ whenever necessary.

FIG. 6 shows a case in which the above operations are used in aneducational presentation in which a teacher teaches arithmetic problemsto students. In this case, an additional image b110 which is selected bythe device 102 is synthesized with a main image A110 by the device 101,the synthesized image A110+b110 is input into the device 101, a pointimage a110 is synthesized with the synthesized image A110+b110, and thesynthesized image A110+b110+a110 is displayed on the displays 114 and114′ of the devices 101 and 102.

FIG. 7 shows a case in which three material presentation devices, thatis, the device 101, the device 102, and a device 103 are connected in adaisy chain and the synthesized image is shared among the devices 101 to103 while a point image is synthesized with a main image in turn of thedevice 101, device 102, and the device 103. The device 103 has thesubstantially same structure as that of the device 101, and referencenumerals of the components in the device 103 are attached with an affix“″” to the reference numerals of the components in the device 101. Sincethe components in the device 103 are identical to those of the device101, detailed explanations for the components in the device 103 will beomitted. The outputs 11B and 12B of the device 101 are respectivelyconnected to the inputs 11A′ and 12A′ of the device 102 next thereto,the outputs 11B′ and 12B′ of the device 102 are respectively connectedto the inputs 11A″ and 12A″ of the device 103 next thereto, and theoutputs 11B″ and 12B″ of the device 103 are respectively connected tothe inputs 11A and 12A of the device 101 next thereto, whereby the mainimage and the point image are transmitted so as to be circulated in aone-way path. FIG. 7 shows a case of exchanging the images describedbelow. An image A1 which is stored in the device 101 is set as the mainimage of the devices 101 to 103. Next, a pointing operation is performedusing the device 101, whereby a point image a1 is synthesized with themain image A1, and the synthesized image A1+a1 is output to the devices102 and 103. The input 11A button 171 of the image selecting section 170is pressed in order to input the synthesized image into the device 101itself. A point image b1 is synthesized with the synthesized image A1+a1by the device 102, and the synthesized image A1+a1+b1 is transmitted tothe devices 103 and 101. Next, a point image c1 is synthesized with thesynthesized image A1+a1+b1, and the synthesized image A1+a1+b1+c1 istransmitted to the devices 101 and 102. The synthesized imageA1+a1+b1+c1 is thereby shared with the devices 101 to 103.

According to the material presentation device in the first embodiment,plural users can add additional images to the main image, exchange andshare the synthesized images among each other, and simultaneouslycommunicate with each other based on the shared images so that it is notnecessary to use conventional external image processing devices. Inaddition, the material presentation device itself has a synthesizedimage displaying function, whereby conventional image processing devicesare not necessary, a structure of the material presentation device forsharing an image can be designed simply, and setting for communicatingan image with each other can be performed by an easy operation ofbuttons.

(2) Second Embodiment

(A) Constitution of Material Presentation Device

FIG. 8 systematically shows a state in which image data and voice dataare communicated with each other by material presentation devices 201and 202 (hereinafter these material presentation devices are calleddevices 201 and 202 for short) in a second embodiment according to thepresent invention. The devices 201 and 202 have the substantially samestructure, and reference numerals of the components in the device 202are attached with an affix “′” to the reference numerals of thecomponents in the device 201. Since the components in the device 202 areidentical to those of the device 201, detailed explanations for thecomponents in the device 202 will be omitted. The device 201 is equippedwith a material mounting pedestal 211, a photographing section 213,provided on the material mounting pedestal 211 via an arm 212, whichphotographs a material S2, for example, a document on the materialmounting pedestal 211, a display (image displaying section) 214, and aspeaker-microphone 215 which inputs and outputs voice. The display 214is provided at the back side of the set position of the material on thematerial mounting pedestal 211, and is set at a backward inclinedattitude toward an user (not shown) who is in front of the materialmounting pedestal 211.

The photographing section 213 is equipped with a camera 213 a and anoptical filter 213 b which enables the camera 213 a to photograph onlyinfrared light. The optical filter 213 b is removably placed in thephotographing optical path of the camera 213 a. The optical filter 213 bis switched between a state of being placed in the photographing opticalpath and a state of being removed therefrom by hand or by automaticcontrol. In the state of being removed therefrom, the camera 213 aphotographs the material S2, and the photographed image by the camera213 a is displayed on the display 214.

An operation of reading pointing information is described hereinafter.In FIG. 8, reference numeral 220 denotes a pen which is used toindicate, for example, a specific part of the material S2 by the user. Apointing mark 221 is provided at the leading tip portion of the pen 220which emits infrared light. The pointing mark 221 is composed of a lightemitting diode (LED) which emits light by changing a switch to ON. Theuser performs a pointing operation on a required part with the pointingmark 221 of the pen 220.

An image which is displayed on the respective displays 214 and 214′ ofthe devices 201 and 202 is input into and output to each other, and thesame image is displayed on the displays 214 and 214′. That is, the sameimage is shared with the devices 201 and 202. The voice data which areinput into the speaker-microphones 215 and 215′ are input into andoutput to each other, and the voice data which are input intospeaker-microphone 215 of the device 201 are output from thespeaker-microphone 215′ of the device 202. A mutual communicating devicefor images and voices are selected appropriately according to the setpositions of the devices 201 and 202 or interfaces, and is composed of acable 230 for communication in FIG. 8. As shown in the tables belowschematic diagram of the device 201 in FIG. 8, the device 201 has aninput 21A (first input section) and an output 21B (first output section)for changing a main image with the device 202, and has an input 22A(second input section) and an output 22B (second output section) forchanging point information with the device 202. The input 21A isconnected to the output 21B′ of the device 202, and the input 22A isconnected to the output 22B′ of the device 202.

The above devices 201 and 202 enable communicating usingspeaker-microphones 215 and 215′ while sharing an image displayed on therespective displays 214 and 214′, enable synthesizing of a point imageas an additional image with a main image, and enable sharing of thesynthesized image each time.

The main image is shared with the respective devices 201 and 202. On thepart of the device 201, a camera image (an object of the camera image isthe material S2, etc.) which is photographed by the camera 213 a isselected as the main image. A memory image is stored in an internalmemory device which is provided in the device 201 or in an externalmemory device which is removably placed in the device 201. An externalimage which is generated from an external device, for example a personalcomputer, connected to device 201 is selected as the main image. Animage by the device 202, which is input from the output 21B′ of thedevice 202 into the input 21A of the device 201, is selected as the mainimage. This image by the device 202 is one of the camera image, thememory image and the external image, which are stored in the device 202.

As shown in FIG. 9, an image selecting panel 216 is provided on thedevice 201. The image selecting panel 216 is equipped with a main imageselecting section 270 and an output image selecting section 280. Themain image selecting section 270 has buttons for selecting one imageeither by the device 201 or by the device 202 as the main image. Theoutput image selecting section 280 has buttons for selecting one imageas the main image from the above images when one image by the device 201is selected as the main image, that is, which of the above images isselected as the output image from the output 21B of the device 201.

The main image selecting section 270 has an input 21A button 271 forselecting an image, which is input from the device 202 into the device201, as the main image, and an output 21B button 272 for selecting animage by the device 201 as the main image and outputting the main imagefrom the output 21B to the device 202. The output image selectingsection 280 has a camera button 281 for selecting the camera image bythe device 201, a memory button 282 for selecting the memory image ofthe device 201, a personal computer button 283 for selecting theexternal image which is input from the external device (in this case, apersonal computer) connected to the device 201, and a reserve button 284for selecting one image other than these images.

FIG. 10A is a functional block diagram showing the execution of an imagesynthesizing function using the device 201, and FIG. 11A is the samefunctional block diagram in the case of using the device 202. Thefigures facilitate understanding of the processes for images, which areinput into and output to these devices, in “operation of materialpresentation device” described below, although these devices have thesame structure. Explanations for the execution of an image synthesizingfunction using the device 202 will be omitted.

The device 201 has an image synthesizing circuit (image synthesizingsection) 240 which synthesizes plural input images by an ordinary imagesynthesizing method. The image by the device 201 or the image outputfrom the device 202 is input as the main image into the imagesynthesizing circuit 240. One image is selected as the main image of thedevice 201 from the camera image, the memory image and the externalimage. The main image is input into a first frame memory 251 via aninput line 241, and is temporary stored therein. The image output fromthe device 202 is input from the input 21A into a second frame memory252 via an input line 242, and is temporary stored therein. The image bythe device 201 or the image output from the device 202 is selected by aselector 261, and is input as the main image into the image synthesizingcircuit 240. When the image by the device 201 is selected as the mainimage by the selector 261, the main image is output from the first framememory 251 to the input 21A′ of the device 202 via the output 21B. Inthis case, a changing operation of setting the selector 261 is performedby pressing either the input 21A button 271 or the output 21B button 272of the main image selecting section 270 on the above image selectingpanel 216.

The point information related to the point image which is added to themain image is input from the output 22B′ of the device 202 into theinput 22A, and the point information is input into a point imagegenerating section (point image generating device) 245. The pointinformation of the device 201 is also input into the point imagegenerating section 245. The point information of the device 201 isoutput from the output 22B to the input 22A′ of the device 202. Thepoint image is generated by the point image generating section 245 basedon the input point information. The point image generated thereby isinput from an input line 243 into the image synthesizing circuit 240.

As described above, the main image is communicated in the communicationsystem of the inputs 21A and 21A′/outputs 21B and 21B′ of the devices201 and 202, and the point information related to the point image whichis added to the main image is communicated in the communication systemof the inputs 22A and 22A′/outputs 22B and 22B′ thereof. In this case,the point information which is communicated in the communication systemof the inputs 22A and 22A′/outputs 22B and 22B′ is image informationwhich is needed to generate the point image. The point information inputinto the point image generating section 245 is described below.

(a) Function information: for example, a function of a pointer whichindicates a specific part, a function for drawing lines by connectingloci of the pointer, and a function for eliminating a specific part.

(b) Detail information: for example, a shape of a pointer whichcorresponds to the function.

(c) Color information: for example, a color of a point image.

(d) Position information: for example, a position of an indication markbased on X coordinates and Y coordinates.

In addition, transmitting class information other than the above pointinformation, for example, announcement information of transmitting themain image, a designation of a device of transmitting destination(transmitting destination is the device 201 or the device 202, or bothof them), and a designation of the device of transmitting master (device201 or device 202), is transmitted in the communication system of theinputs 22A and 22A′/outputs 22B and 22B′.

In order to generate the point image by the point image generatingsection 245, for example, memory devices are prepared for the device 201and the device 202 respectively, and a point image is generated by thememory device which is selected. In addition, instead of using the abovememory devices, it is possible to store point information of the bothdevices and generate a point image

The point image generated by the point image generating section 245 issynthesized with the main image, which is selected by the selector 261,(either the image by the device 201 or the image which is input from theoutput 21B′ of the device 202 into the input 21A of the device 201), bythe image synthesizing circuit 240, and the synthesized image isdisplayed on the displays 214 and 214′. The synthesized image thereby isshared by the users of the devices 201 and 202.

(B) Pointing Function with a Pen

A pointing operation can be performed on a specific part of the materialS2 on the material mounting pedestal 211 using the photographing section213 and the pointing mark 221 of the pen 220 without the shadow of thepen 220 and the user's hand falling on a displaying screen. The pointingfunction is described below. Explanations for the action of the pointingfunction of the device 202 will be omitted since the action of thepointing function of the device 202 is the same as that of the device201.

XY coordinates of a virtual screen are set within a photographing viewangle of the camera 213 a on the upper surface of the material mountingpedestal 211, that is, the material mounting surface by an ordinaryimage analysis. A method of setting the virtual screen is describedbelow. The pointing mark 221 of the pen 220 emits light in turn at twodiagonal corner points at least within the photographing view angle ofthe camera 213 a while the optical filter 213 b is placed in thephotographing optical path. The above state in which the pointing mark221 of the pen 220 emits light is photographed by the camera 213 a andthe positions of the pointing mark 221 which are light emitting pointsare recognized based on the image data by the camera 213 a. The XYcoordinates of the virtual screen are generated by an image processingtechnique. As a result, the invisible virtual screen is set on thematerial mounting pedestal 211, and is fixed as long as the intervalbetween the camera 213 a and the material mounting pedestal 211 is notchanged. That is, the operation of setting the virtual screen may beperformed once as an initial setting. When the material S2 is placed onthe material mounting pedestal 211 and the pointing operation isperformed thereon, the virtual screen is set within the overallphotographing view angle, whereby it is possible to perform the pointingoperation directly on the position of the material S2.

When the material S2 is placed on the material mounting pedestal 211,the virtual screen is set on the material S2. When the pointingoperation is performed, the pointing mark 221 of the pen 220 emits lighton the material S2 while the optical filter 213 b is placed in thephotographing optical path. As a result, the pointing mark 221 isphotographed by the camera 213 a, and the position coordinates of thepointing mark 221 on the coordinates of the virtual screen aresequentially calculated based on the image data. The point image whichis in a shape of, for example, an arrow, is generated on the positioncoordinates of the pointing mark 221 which are calculated by the pointimage generating section 245.

(C) Operation of Material Presentation Device

An example of operations of the above material presentation devices 201and 202 is described hereinafter.

FIG. 10B is a flow chart showing operations of the device 201. As shownin the figure, the image either by the device 201 or by the device 202is selected as the main image by the device 201, and one image isselected as the main image from the above images when the image by thedevice 201 is selected as the main image (in step S211). In this case,an image A2 by the device 201 is selected as the main image, and theoutput 21B button 272 of the main image selecting section 270 on theabove image selecting panel 216 and one of the buttons 281 to 283 of theoutput image selecting section 280 are pressed. As a result, the imageA2 which is set to be the main image of the device 201 is input into theimage synthesizing circuit 240, and is also input from the output 21Binto the input 21A′ of the device 202. The image A2 which is input intothe image synthesizing circuit 240 is displayed on the display 214 ofthe device 201. One example of the image A2 is shown in the upper leftside of the flow chart of the device 201 in FIG. 12.

As shown in a flow chart in FIG. 11B, in the case of the device 202, theimage either by the device 201 or by the device 202 is selected as themain image which is shared with the devices 201 and 202 (in step S221).In this case, since the image A2 by the device 201 is selected as themain image as described above, the input 21A′ button 271′ of the mainimage selecting section 270′ on the image selecting panel 216′ ispressed, whereby the image A2, which is output from the output 21B ofthe device 201, is input into the input 21A′ of the device 202, is inputinto the image synthesizing circuit 240′, and is displayed on thedisplay 214′.

On the part of the device 201, a pointing operation is performed usingthe pointing mark 221 of the pen 220 on the material S2 as describedabove (in step S212), whereby point information of a point image a2(shown in the upper center of the flow chart of the device 201 in FIG.12) is input from the output 22B of the device 201 into the input 22A′of the device 202, and is input into the point image generating section245. The point image a2 based on the point information is generated bythe point image generating section 245, and the point image a2 is inputinto the image synthesizing circuit 240 and is synthesized with theimage A2 thereby. The synthesized image A2+a2 which is synthesizedthereby is output to the display 214, and is displayed on the display214 (shown in the upper right side of the flow chart of the device 201in FIG. 12). On the other hand, on a part of the device 202, the pointimage a2 is generated by the point image generating section 245′, basedon the point information which is input from the device 201 into theinput 22A′ (shown in the upper center of the flow chart of the device202 in FIG. 12). The point image a2 is synthesized with the image A2 bythe image synthesizing circuit 240′, and the synthesized image A2+a2 isdisplayed on the display 214′ (shown in the upper right side of the flowchart of the device 202 in FIG. 12). As a result, the synthesized imageA2+a2 is displayed on both displays 214 and 214′ of the devices 201 and202.

While seeing the synthesized image A2+a2 on the display 214′, the userof the device 202 performs a pointing operation on a desired part of thesynthesized image A2+a2 using the pointing mark 211′ (in step S222).Point information of a point image b2 (shown in the lower left side ofthe flow chart of the device 202 in FIG. 12) is output from the output22B′ to the input 22A of the device 201, and is input into the pointimage generating section 245′ of the device 202. On the part of thedevice 202, the point image b2 based on the point information isgenerated by the point image generating section 245′, and the pointimage b2 is input into the image synthesizing circuit 240′. The pointimage b2 is synthesized with the image A2+a2 thereby. The synthesizedimage A2+a2+b2 is displayed on the display 214′ (in step S223: shown inthe lower right side of the flow chart of the device 202 in FIG. 12).

On the other hand, on the part of the device 201, the point informationof a point image b2 is input from the device 202 into the input 22A, andthe point image b2 is generated by the point image generating section245 based on the point information (shown in the lower left side of theflow chart of the device 201 in FIG. 12). The point image b2 is inputinto the image synthesizing circuit 240, is synthesized with thesynthesized image A2+a2 thereby, and the synthesized image A2+a2+b2 isdisplayed on the display 214 (in step S213: shown in the lower rightside of the flow chart of the device 202 in FIG. 12). As a result, thesynthesized image A2+a2+b2 displayed on both displays 214 and 214′ ofthe devices 201 and 202 is shared by the users of the devices 201 and202.

Next, when an image B2 by the device 202 is selected as the main image,image synthesizing operations proceed in the above manner as shown insteps S214 and S 215 in FIG. 10B and in steps S224 and S225 in FIG. 11B.

As described above, it is possible to add the point image to thesynthesized image (at first, the main image) which is output to thedisplays 214 and 214′ of the devices 201 and 202 and is shared thereby.In this case, it is possible to communicate using speaker-microphones215 and 215′ whenever necessary.

FIG. 13 shows a case in which three material presentation devices, thatis, the device 201, the device 202 and a device 203 are connected in adaisy chain and the synthesized image is shared thereby. The device 203has the substantially same structure as that of the device 201, andreference numerals of the components in the device 203 are attached withan affix “″” to the reference numerals of the components in the device201. Since the components in the device 203 are identical to those ofthe device 201, detailed explanations for the components in the device203 will be omitted. The outputs 21B and 22B of the device 201 arerespectively connected to the inputs 21A′ and 22A′ of the device 202next thereto, the outputs 21B′ and 22B′ of the device 202 arerespectively connected to the inputs 21A″ and 22A″ of the device 203next thereto, and the outputs 21B″ and 22B″ of the device 203 arerespectively connected to the inputs 21A and 22A of the device 201 nextthereto, whereby the main image and the point image are transmitted soas to be circulated in a one-way path. A case in which an image which isstored by the device 201 is transmitted as the main image from thedevice 201 to the devices 202 and 203 and the point images by thedevices 201 to 203 are added to the main image, is described below.

The device 201 transmits the announcement information of transmittingthe main image, from the output 22B to the device 202, and waits for theacceptance information which is transmitted from the devices 202 and203. The device 202 transmits the announcement information, which istransmitted from the device 201, as it is from the output 22B′ to thedevice 203, and transmits the acceptance information thereof from theoutput 22B′ to the device 203. The device 203 transmits the announcementinformation, which is transmitted from the device 202, as it is from theoutput 22B″ to the device 201, and transmits the acceptance information,which is transmitted from the devices 202 and 203, from the output 22B″to the device 201. The device 201 accepts the acceptance informationfrom the devices 202 and 203, and transmits the main image from theoutput 21B to the device 202. The main image is transmitted to thedevices 202 and 203, and is displayed on the displays 214 to 214″ of thedevices 201 to 203. In this state, pointing operations are performedappropriately using the devices 201 to 203, the point information of thepoint images is transmitted in the communication system of the inputs22A to 22A″/outputs 22B to 22B″ as described below.

The device 201 generates a point image based on point information, whichis input into the input 22A, (point information transmitted from thedevice 202 and/or the device 203) and point information of the device201 itself, synthesizes the point image with the main image, anddisplays the synthesized image on the display 214. The device 201 doesnot output an image which is input from the input 21A, and does notoutput point information which is input from the input 22A when thepoint information is one which is transmitted from the device 201itself.

The device 202 generates a point image based on point information, whichis input into the input 22A′, (point information transmitted from thedevice 201 and/or the device 203) and point information of the device202 itself, synthesizes the point image with the main image, anddisplays synthesized image on the display 214′. The device 202 does notoutput an image which is input from the input 21A′, and does not outputpoint information which is input from the input 22A′ when the pointinformation is one which is transmitted from the device 202 itself.

The device 203 generates a point image based on point information, whichis input into the input 22A″, (point information transmitted from thedevice 201 and/or the device 202) and point information of the device203 itself, synthesizes the point image with the main image, anddisplays synthesized image on the display 214″. The device 203 does notoutput an image which is input from the input 21A″, and does not outputpoint information which is input from the input 22A″ when the pointinformation is one which is transmitted from the device 203 itself.

According to the material presentation device in the second embodiment,plural users can add point images to the main image and share thesynthesized image with each other so that it is not necessary to use theconventional external image processing devices. Thus, a structure of thematerial presentation device for sharing an image can be designedsimply, and setting operations for communicating images with each othercan be performed by an easy operation of buttons.

In addition, instead of outputting the synthesized image to anothermaterial presentation device, the point information which is needed togenerate the point image is output, the point image is generated by thepoint image generating section 245 of another material presentationdevice into which the point information is input, and is synthesizedwith the main image by the image synthesizing circuit 240 thereof. Thus,transmitted point information is much less than image data ininformation content and in capacity thereof, whereby communicationtraffic is greatly reduced. As a result, it is possible to reduce thetime in communicating and displaying images, and to make imagedisplaying actions smoother. Furthermore, as shown in FIG. 13, it iseasy to connect three or more material presentation devices, and tocommunicate with each other while sharing images widely.

1. A material presentation device connecting at least two materialpresentation devices to each other, comprising: a material mountingpedestal having a material mounting surface on which material ismounted; a photographing section for photographing the material; a firstselecting device for selecting one image as a main image from pluralimages composed of an image output by another material presentationdevice, a camera image of a material on the material mounting pedestal,which is photographed by the photographing section, an image stored in amemory device, and an external image output by an external deviceconnected thereto; a second selecting device capable of selecting noimage or one image as an additional image from plural images composed ofa camera image of a material on the material mounting pedestal, which isphotographed by the photographing section, an image stored in the memorydevice and an external image output by the external device; a virtualscreen which is set on the material mounting surface; a pointing markfor setting the virtual screen and for being used by a user to operate apoint on the virtual screen; a point image generating device forgenerating a point image from point information which is subtracted froman image of the virtual screen and the pointing mark photographed by thephotographing section; an image synthesizing section for synthesizingthe additional image selected by the second selecting device and thepoint image with the main image selected by the first selecting device;a display image selecting device for selecting one image from an imageoutput by another material presentation device and the image synthesizedby the image synthesizing section; an image displaying section fordisplaying the image selected by the display image selecting device; animage outputting section for outputting the image synthesized by theimage synthesizing section; and an optical filter which is removablyprovided to the photographing section and which enables thephotographing section to photograph only light emitted from the pointingmark, wherein when the user sets two arbitrary reference points by usingthe pointing mark on the material mounting surface, the photographingsection photographs the two reference points, and coordinates on thevirtual screen are generated by an image processing technique from aphotographed image of the two arbitrary reference points photographed bythe photographing section, so that the virtual screen is set to have arectangular area based on the two arbitrary reference points.
 2. Amaterial presentation device connecting at least two materialpresentation devices to each other, comprising: a material mountingpedestal having a material mounting surface on which material ismounted; a photographing section for photographing the material; aselecting device for selecting one image as a main image from pluralimages composed of an image output by another material presentationdevice, a camera image of a material on the material mounting pedestal,which is photographed by the photographing section, an image stored in amemory device, and an external image output by an external deviceconnected thereto; a virtual screen which is set on the materialmounting surface; a pointing mark for setting the virtual screen and forbeing used by a user to operate a point on the virtual screen; a pointimage generating device for generating a point image as an additionalimage from point information output by another material presentationdevice and point information which is subtracted from an image of thevirtual screen and the pointing mark photographed by the photographingsection; an image synthesizing section for synthesizing the main imageselected by the selecting device with the additional image generated bythe point image generating device; an image displaying section fordisplaying the image synthesized by the image synthesizing section; afirst outputting section for outputting the main image which is selectedfrom plural images composed of the camera image of a material on thematerial mounting pedestal, which is photographed by the photographingsection, the image stored in the memory device, and the external imageoutput by the external device connected thereto; a second outputtingsection for outputting point information which is subtracted from theimage photographed by the photographing section; a first inputtingsection for inputting the main image which is output by the firstoutputting section of another material presentation device; a secondinputting section for inputting point information which is output by thesecond outputting section of another material presentation device; andan optical filter which is removably provided to the photographingsection and which enables the photographing section to photograph onlylight emitted from the pointing mark, wherein when the user sets twoarbitrary reference points by using the pointing mark on the materialmounting surface, the photographing section photographs the tworeference points, and coordinates on the virtual screen are generated byan image processing technique from a photographed image of the twoarbitrary reference points photographed by the photographing section, sothat the virtual screen is set to have a rectangular area based on thetwo arbitrary reference points.